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Diffstat (limited to 'Doc/library/atexit.rst')
| -rw-r--r-- | Doc/library/atexit.rst | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/Doc/library/atexit.rst b/Doc/library/atexit.rst index 01cf379df2..dbdd81e6d0 100644 --- a/Doc/library/atexit.rst +++ b/Doc/library/atexit.rst @@ -9,13 +9,14 @@ The :mod:`atexit` module defines functions to register and unregister cleanup functions. Functions thus registered are automatically executed upon normal -interpreter termination. The order in which the functions are called is not -defined; if you have cleanup operations that depend on each other, you should -wrap them in a function and register that one. This keeps :mod:`atexit` simple. +interpreter termination. :mod:`atexit` runs these functions in the *reverse* +order in which they were registered; if you register ``A``, ``B``, and ``C``, +at interpreter termination time they will be run in the order ``C``, ``B``, +``A``. -Note: the functions registered via this module are not called when the program -is killed by a signal not handled by Python, when a Python fatal internal error -is detected, or when :func:`os._exit` is called. +**Note:** The functions registered via this module are not called when the +program is killed by a signal not handled by Python, when a Python fatal +internal error is detected, or when :func:`os._exit` is called. .. function:: register(func, *args, **kargs) @@ -67,8 +68,9 @@ automatically when the program terminates without relying on the application making an explicit call into this module at termination. :: try: - _count = int(open("counter").read()) - except IOError: + with open("counterfile") as infile: + _count = int(infile.read()) + except FileNotFoundError: _count = 0 def incrcounter(n): @@ -76,7 +78,8 @@ making an explicit call into this module at termination. :: _count = _count + n def savecounter(): - open("counter", "w").write("%d" % _count) + with open("counterfile", "w") as outfile: + outfile.write("%d" % _count) import atexit atexit.register(savecounter) |